1. Field of the Invention
This invention relates to the field of photonics, and in particular to a monitor for monitoring the performance of photonic devices in an optical network, such as demultiplexers employed in wavelength division multiplexing. The monitor can, for example, accurately measure the power, wavelength, and ONSR (Optical Signal-to-Noise Ratio) for each channel.
2. Description of Related Art
Telecommunications carriers have a need to monitor the performance of optical transport networks. For example, light will often undergo a slight wavelength shift as light source (typically a semiconductor laser) ages and starts to fail. The telecommunications carriers need to be able to monitor this.
A number of manufacturers offer monitoring devices, but none is capable of effectively monitoring channel power, wavelength, and OSNR, and yet at the same time have a small footprint without moving parts and be scaleable. Prior art devices also have limited channel capacity. For example, Kymata Ltd. offers a DWDM Power Monitor that is suitable for active monitoring of optical power levels within a DWDM system. However, this device, which uses AWG (Arrayed Waveguide Grating) technology is not capable of monitoring wavelength or OSNR and is limited to 40 channels. AWG technology has poor scaleability.